title: Evolution and homoplasy at the Bem6 microsatellite locus in three sweetpotato whitefly (Bemisia tabaci) cryptic species.
abstract: BACKGROUND
  The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within species homoplasy can lead to an underestimate of differentiation among populations and among species homoplasy can produce a misleading interpretation regarding shared alleles and hybridization. This is especially problematic with cryptic species.
  
  
  RESULTS
  By sequencing alleles from three cryptic species of the sweetpotato whitefly (Bemisia tabaci), designated MEAM1, MED, and NW, the evolution of the putatively dinucleotide Bem6 (CA₈)imp microsatellite locus is inferred as one of primarily stepwise mutation occurring at four distinct heptaucleotide tandem repeats. In two of the species this pattern yields a compound tandem repeat. Homoplasy was detected both among species and within species.
  
  
  CONCLUSIONS
  In the absence of sequencing, size homoplasious alleles at the Bem6 locus lead to an overestimate of alleles shared and hybridization among cryptic species of Bemisia tabaci. Furthermore, the compound heptanucleotide motif structure of a putative dinucleotide microsatellite has implications for the nomenclature of heptanucleotide tandem repeats with step-wise evolution.
authors.affiliation: USDA-ARS, U.S. Horticultural Research Laboratory, 2001 South Rock Rd, Fort Pierce, FL 34945, USA.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Dickey
authors.forename: Paula M
authors.initials: PM
authors.lastname: Hall
authors.forename: Robert G
authors.initials: RG
authors.lastname: Shatters
authors.forename: Cindy L
authors.initials: CL
authors.lastname: Mckenzie
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D019143:Evolution, Molecular; D006430:Hemiptera / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics*; D018895:Microsatellite Repeats / Q000235:genetics*; D008969:Molecular Sequence Data; D020080:Tandem Repeat Sequences
chemical_list: D019476:Insect Proteins